National Instruments NI 9213, Getting Started

Minimizing Thermal Gradients

Changes in the ambient air temperature near the front connector or a thermocouple

wire conducting heat directly to terminal junctions can cause thermal gradients.

Observe the following guidelines to minimize thermal gradients and improve the

system accuracy.

■

Use small-gauge thermocouple wire. Smaller wire transfers less heat to or

from the terminal junction.

■

Run thermocouple wiring together near the spring-terminal connector to

keep the wires at the same temperature.

■

Avoid running thermocouple wires near hot or cold objects.

■

Minimize adjacent heat sources and air flow across the terminals.

■

Keep the ambient temperature as stable as possible.

■

Make sure the NI-9213 terminals are facing forward or upward.

■

Keep the NI-9213 in a stable and consistent orientation.

■

Allow the thermal gradients to settle after a change in system power or in

ambient temperature. A change in system power can happen when the

system powers on, the system comes out of sleep mode, or you insert/remove

modules.

■

Use the NI 9940 backshell kit.

■

If you connect any extension wires to thermocouple wires, use wires made

of the same conductive material as the thermocouple wires.

Overvoltage Protection

The NI-9213 provides overvoltage protection between any two inputs.

Note

 Refer to the device datasheet on 

ni.com/manuals

 for more

information about overvoltage protection.

ni.com

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NI-9213 Getting Started